Process of preparing concentrated hydrated magnesia.



UNITED srArEs PATENT orricn wiurmLosoo'rr MORRISON, or SAN FRANCISCO, CALIFORNIA.

PROCESS milky preparation of hydrated magnesiumoxid to a soft pasty mass,

useful for various purposes, but especially valuable as a base for tooth paste.

Magnesium oxid, prepared by precipitating the oxid from a solution of a soluble magnesium salt with the aid of a soluble caustic alkali, is a simple and well known chemical process and can be carried out with little preparation and apparatus. It is also known that if the freshly precipitated magnesium 'oxid be subjected to aprolonged boiling in water, its character, nature, or condition is changed in such manner that it will no longer subside or settle as when first precipitated, but remains in suspension in the water forming a milky looking liquid, and for that reason called milk of magnesil, more correctly hydrated magnesium 0X1 The concentrated hydrated magnesium oxid or magnesium magma may be prepared by first precipitating magnesium oxid from a hot solution ofmagnesium sulfate by the aid of a solution of potassium hydroxid or sodium hydroxid; or magnesium chlorid may be used in conjunction with either of the aforementioned alkalies, It is, how ever, preferred to use magnesium sulfate and precipitate the magnesium oxid with sodium hydroxid.

After precipitating the magnesium oxid it is then decanted and boiled with fresh water each day for aboutsix days. Following this treatment and appears as a white or milky looking liquid produced lent particles of magnesium oxid held in suspension therein which will not separate nor settle appreciably upon standing, and

with a specific gravity of 104.8 thereabouts.

by the finely divided fioccui Specification of Letters Patent. I Application mad January 30, 1908.

the hydrated magnesium oxid is Withdrawn from the boiling tank in concentrating proper,

'be of the right base for tooth paste.

properties OF PREPARING GONCENTRATED HYDRATE D MAGNESIA.

Patented Oct. 13, 1908.

s 'al No. 413,436.

Having thus obtained; the milk of magnesla 1n liquld form it becomes necessary to reduce the oxid toa soft unctuous mass of.

plastic consistency and without any appreciable amount of free water. The success of; thisstep depends upon the care exercised the milk of magnesia. This liquid is first poured upon a cloth strainer, returning again and again the first portion that passes through until the liquid runs clear. When all the liquid has passed through'the strainer,the concentrate is left to drain thoroughly. This requires about six days, after which the concentrate or magma is squeezed through a fine linen strainer and spread out to dry, preferably upon trays in a dry room kept at a tempera ture of about 100 degrees F. The trays are for convenience, arranged in a rack and are drawn: out each day and the magma thoroughly mixed, a necessary operation to prevent'lumps or granular crusts from forming in the mass. The drying proceeds slowly under this treatment and requires from five to ten days according to the humidity of the atmosphere. When the magma appears to consistency the contents of all the trays are mixed together in a large container and weighed. Should the need of further concentration be developed, the mass is again spread on the trays and subjected to further drying until in proper condition for the purpose desired, best determined by experience.

The temperature of the drying room rapid drying has an injurious efiect upon the preparation by destroying in a greater or lesser degree which renders the magma so valuable as a The magma has other which increase its worth as it is anti-acid and unique in that it is free from sugar, glucose, soap, and other more or less harmful substances; it is a mild alkali and s aringly soluble in a neutral or alkaline liquid, but freely soluble in acidulous liquids which it quickly neutralizes.

Since most injury to the teeth is caused by acids generated from saccharine or similar substances lodged between the teet the magma or concentrated hydrated magnesium oxid, acting as a-rapid neutralizer of the acids, prevents decay of the teeth and also acts as a specific for the removal of tartar, being a solvent of such deposits.

should not exceed 100 degrees F., as a too' the unctuous consistency t I claim 1. The process of eoncentratmg hydrated magnesium oxid consisting lll SlIbjCCtlllg magnesium oxidto prolonged boiling in' water whereby its condition is changed and hydrated n'iagnesiuni oxid is formed, separating the same from the bulk of its free water by repeated straining, then allowing the concentrate to drain for a nun'iber of days, afterwards squeezing it through a fine strainer, and finally subjecting it to a temperature of about one hundred degrees F. until snfliciently dry for use, the products being thoroughly stirred While drying.

2. The process of concentrating milk of magnesia which consists in passing the milk of magnesia repeatedly through a strainer until it runs clear and the hydrated magnesiuni oxid remains in the strainer, then let the concentrate drain 'l'or about six days atter which it is squeezed through a line strainer, and linally subjected to a temperature of about one hundred degrees l until sullieiently dry for use, the substance being thoroughly stirred while drying.

In testimony. that I claim the foregoing as my own, I have hereto allixed my signature 1n the presence of two witnesses.

WlNl lElil) SCOTT lllOlllllSUN Witnesses V. \V. W onnnN, A. H. FLYNN. 

